Process for preparing urea by steps with differentiated yield, and relevant implementations also on existing plants

Process for preparing urea by steps with differentiated yield, and relevant implementations also on existing plants

  • CN 1,052,975 C
  • Filed: 10/04/1991
  • Issued: 05/31/2000
  • Est. Priority Date: 10/05/1990
  • Status: Active Grant
First Claim
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1. method of improving the device of existing production urea, this device comprise be used for urea synthesis reactor (R2) and be used for from the aqueous solution (SC) of the unreacted product of leaving reactor (R2), isolating the recirculation section (SE-RI) of urea, reactor (R2) is communicated with recirculation section (SE-RI) fluid, and this method comprises the following steps:

  • A) another parallel with the reactor (R2) of existing apparatus reactor (R1) that is used for urea synthesis is installed;

    B) described reactor (R1) and recirculation section (SE-RI) and the equipment that adds high purity ammonia and carbonic acid gas are coupled together;

    C) in the downstream of described reactor (R1) separator (SEP) is installed and is separated into the steam (VF) of flash distillation and the urea soln (SUF) after the flash distillation with the reaction mixture that will come out from reactor (R1);

    D) equipment of recirculation flash-off steam (VF) to the reactor (R2) of existing apparatus that is used for is installed;

    E) urea soln (SUF) be used for adding after the flash distillation equipment to urea recirculation section (SE-RI) is installed;

    F) pipeline (7) being installed between the reactor (R2) of described recirculation section (SE-RI) and existing apparatus is used for described unreacted product solution (SC) is added in the reactor (R2);

    G) pipeline (6) being installed between described recirculation section (SE-RI) and described reactor (R1) is recycled in the reactor (R1) with the high purity ammonia (NEP) that will reclaim.

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